PR #20 made routingHint, code and details required on CultNetErrorMessage; six call sites in
cultmesh-ts still built the message without them, so build:ts failed with TS2345. cultnet-ts
now owns cultNetTextError(error), the legacy-union decode uses it too, and the call sites
and two test expectations call it. The types are unchanged.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>